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Volumetrics? (fog)

Posted: Tue May 29, 2018 8:36 pm
by Edward Henry
Has anyone successfully used the Volumetrics extension in Rhino to make a fog sort of effect?
I've chewed through what little info I can find online but I'm getting kind of bizarre results. Render looks okay in Fire preview, but when I start a "real" render it shows a bit of the image and then seems to paint over that with strange shards of black until there's nothing to see (except black). Examples of Fire and Maxwell renders attached. (maxwell results at top, fire preview at bottom)

Well... that rendering that came out all black: if I stop the rendering in Maxwell and then click the Render button (start/stop render), the "new" Maxwell rendering matches the Fire preview. I've never seen that kind of behavior before. I'm somewhere between shocked and stumped.
As I prepared screenshots for this update I'm getting some *new* new behavior: initial rendering with fog shows some darkening of background. When I Stop that and click Render button again... I get fog that matches Fire preview.
fog - initial render inside MR.jpg
fog - rendered again inside MR.jpg
Just to be clear: all these images are from the same MXS file. The dark or black images are the results of the initial rendering launched from inside Rhino. The foggy (correct) images are the renderings I get after Stop/Starting that same rendering from inside Maxwell Render. LOLWUT?

Re: Volumetrics? (fog)

Posted: Thu Jun 07, 2018 10:47 am
by Forum Moderator
Hello Edward,

Usually, those black bars are due to a numeric error somewhere in the scene.
I would try to keep the material of the volumetric as a diffuse white, however, the error could be somewhere else. In my experience, objects with displacement or sss materials are more prone to triggers these types of errors.

I would try removing part of the geometry (just for testing) and see if the error keeps showing until you reduce the scene to the problematic geometry/material.

I hope this helps.